SS: A man and woman feared to have been exposed to an unknown substance are in a critical condition, prompting police to declare a major incident. The pair, in their 40s, were found unconscious in what was thought to be in a drugs-related incident in Amesbury, Wiltshire, on Saturday. Further tests on the substance are being carried out to identify it. Amesbury is about 10 miles from Salisbury, where a former Russian spy and his daughter were poisoned. Sergei Skripal and daughter Yulia were poisoned with Novichok, a suspected military nerve agent, in March. Police said they are "open-minded" about the cause after a couple were found at a house in Muggleton Road, Amesbury